Transmission is essential for survival of pathogen.
Direct transmission; sexually transmitted diseases
Indirect transmission; by vector (arthropods)
Infection by ingestion (food/fecal-oral route)
Infection by inhalation (aerial (lucht) transmission) most dangerous through the air.
Mainly through aerosols (generates by sneezing, talking breathing)
Depends on;
o Pathogen
o Droplet size (druppelgroote)
o Distance (most mo survive poorly in air so transmitted between people
over short distance)
o Conditions (wind, sunlight etc)
Good protection of the skin
Less protection of lung/intestine, because of exchange
Infection respiratory tract; different pathogen infects different parts of respiratory
tract. All pathogens that cause respiratory infection are transmitted through air.
Protection upper tract; common cold
o Ciliated epithelium and mucus; contains antimicrobial peptides and
transport it to stomach/intestine
o Ring of lymph nodes; neemt afvalstoffen op uit je lichaam
Protection lower tract; chronic disease
o Antibmicrobial peptides
o Alveolar (holte) macrophages
Respiratory pathogens
Bacteria
o Streptococci; these diseases are transmitted by airborne droplets or by
direct contact.
Grouping bases on -production of alfa-hemolysin or beta-hemolysin -
antibodies recognize surface antigens; group A (GAS) group B (GBS)
Streptococcus pyogenes; in oral cavity. GAS
Infection and colonization of upper tract.
Causative agent of strep throat (keelontsteking)
Cause infection if epithelial cell layer is damaged
Important virulence factors; capsule and M protein; cover
bacterial surface it binds host proteins which block phagocytosis
and complement activation.
Virulence factor; houdt the streptococci in leven zodat infectie
plaatsvindt
Streptococcus pneumonia; between skull and brain
Colonize upper tract
Can cause pneumonia (longblaasjes komen vol with fluid or pus)
and meningitis (hersenvliesontsteking)
Also, bronchitis, otitis media and sepsis
Virulence factors; capsule enables cell to resist phagocytosis